I have mine set up underneath our kitchen sink and I drilled a whole through the wall so I could hook it up directly to a kent-marine float valve that is hooked up into the sump for auto top off. I don't leave the RO/DI unit on all the time though...I have heard horrow stories of faulty float valves. As far as for water changes, I have a 30 gallon plastic trash can with a cheaper float valve hooked up near the top and I have a "T" in my RO/DI tubing that I hook up whenever it is time to do a water change. I just set the trash can off to the side and let it fill up. Takes about 8 hours or so.